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audioen t1_iujxe26 wrote

This guy sounds like he is totally wrong, but he is roughly correct in that you need low output impedance amplifier to drive variable impedance loads correctly. I am parsing this is what he is talking about, though he doesn't use the right technical terms. He talks about "voltage swings" and "amplifier power", and these are pretty awful ways to describe the problem. Low output impedance is unrelated to having lots of power, or "high" voltage in output side.

Audio is not actually demanding application for electronics. Circuits can switch states at gigahertz rates, and audio is very, very slow signal in comparison, so electronics can trivially follow and reproduce it without ever having to care about real high frequency stuff such as signal path lengths. Power requirements of headsets are also trivial, usually milliwatts or so before they get so loud that your hearing is at risk, and this is still less than would be used by a standby LED of a random home appliance. The voltages needed are similarly on the low side, for a typical lower impedance headset it is probably less than 0.2 V, and this translates to current demands that are a few milliamps, so again, barely anything. Therefore, good enough amplifiers do not need to be large or expensive, but more like finger-nail sized and cost a few bucks to put together. The existence of these external usb soundcards that are often called DAC dongles (but they actually can have dozens of milliwatts of output power) is the proof of what I am saying here.


crod242 t1_iujz4wo wrote

Then what explains the difference most people report between solid state and OTL amps with the HD 600?

I'm sure some of it can be attributed to placebo and justifying the investment in expensive gear, of course. But enough people who otherwise know what they're talking about seem to be convinced, so it's hard to dismiss entirely. I'm not saying you have to spend thousands, but there must be at least some differences between solid state and tube amps.

Are you saying that in this particular case, the sound from the 600 at equal volume would be completely indistinguishable when plugged into either a JDS Atom or something like a Bottlehead Crack?


eckru t1_iuk24d2 wrote

>Then what explains the difference most people report between solid state and OTL amps with the HD 600?

Output impedance.


crod242 t1_iuk3avm wrote

What specific effect does that have on sound quality at similar volume levels? How does that account for warmth, clarity, and other characteristics that people frequently associate with different amp types?